This application relates to a fuel cell system operated in an enclosed environment.
A fuel cell is a device that converts chemical energy of a fuel into electrical energy, typically by oxidizing the fuel. In general, a fuel cell includes an anode and a cathode which are catalyst layers on opposite sides of an electrolytic membrane. When fuel is supplied to the anode and oxidant is supplied to the cathode, the membrane assembly generates a useable electric current that is passed through an external load. In one widely used type of fuel cell, the fuel supplied is hydrogen and the oxidant supplied is oxygen. In such cells, the electrolyte combines the oxygen and hydrogen to form water and to release electrons.
One environment which may benefit from the use of a fuel cell is an enclosed environment such as an unmanned, underwater vehicle. In such a vehicle, it is important to eliminate any gases escaping the vehicle. Thus, waste hydrogen and oxygen along with waste water, which is a product of the operation of fuel cells, cannot be delivered outwardly of the vehicle. This is not an issue with a fuel cell used, as an example, on a land vehicle.
In addition, in operating a fuel cell, it is desirable to periodically purge both the anode and cathode to remove built up impurities. This is typically done by passing hydrogen and oxygen across the anode and cathode, respectively, and into an environment within the underwater vehicle.
However, these gases cannot be left untreated within the environment. Thus, it is known to provide a catalytic oxidizer within the vehicle. Known catalytic oxidizers are operable to remove the hydrogen, such as by combining it with oxygen to create water.
Within the interior of an underwater vehicle, humidity can become high. In addition, there tends to be a good deal of free water due to the operation of the fuel cell.
When the underwater vehicle is within a body of water, the ambient water outwardly of the vehicle can be at low temperatures. This can cause further condensation of the water within the vehicle.
If the catalytic oxidizer is exposed to undue amounts of water, and/or high humidity, its reactivity can be compromised.